The various components that make up a video composition are often captured and edited in different locations. In video production, for example, each of the video, music, sound effects, dialog, and computer-generated imagery may be produced in a different place. In order to review and evaluate the various program components, it is necessary to assemble as many of the components together as possible for viewing. Furthermore, it is important to be able to conduct frequent reviews of work in progress. Current methods involve transport of physical storage media, such as hard drives, file transfer, or the use of shared storage locations maintained in remote servers. In other cases, media is transmitted from remote locations and playback of the transmitted media and local media requires synchronizing the starting playback times of the remotely located components. Most players play the incoming media as it is received while taking into account a fixed delay introduced in transit. If the estimated delay is not long enough to transfer data prior to playback, drop-outs may occur during playback.
Other methods of playback involve special purpose devices that emit clock signals or other special codes to enable devices to synchronize playback, as described, for example, in U.S. Pat. Nos. 6,134,379 and 6,393,198, which are hereby incorporated by reference. Once started, the remote sources of transmitted media continue to run freely, with the risk that as playback proceeds, synchronization will become progressively less precise, and eventually be lost entirely. Other methods involve ensuring that system clocks of each of the participating systems are synchronized, such as by receiving a real-world clock signal or a house reference clock signal.
A practical, timely, accurate method of synchronized playback of the multiple components that comprise a media composition is needed.